Integrated optic devices and photosensitive sol-gel process for producing integrated optic devices

Abstract

A photosensitive sol-gel film containing an organometallic photosensitizer is deposited on the oxide containing surface layer of a silicon substrate. A pattern of white or ultra violet light incident to the photosensitive sol-gel film results in the unbinding of the photosensitizer from the exposed regions of the sol-gel film. A subsequent succession of first and second heating steps results in, first, the removal of the photo sensitizer constituents from the exposed regions of the sol-gel film and, second, the removal of the organic constituents from the exposed regions, resulting in regions doped with a metal oxide with non linear optical properties, such as semicondutive, etc. properties. Optical switches, couplers, waveguides, splitters, interferometers wavelength division multiplexer, Bragg gratings and more can be fabricated. A glass substrate also may be employed, instead of a silicon, in which case a separate silicon oxide surface layer is unnecessary.

1. A method for forming an integrated optic chip including a plurality of waveguiding channels having a longitudinal axis extending from an input to an output end, said method comprising the steps of:
 a. forming a photosensitive sol-gel film including an organometallic photosensitizer on a substrate, the organometallic photosensitizer comprising a metal constituent and a photolabile moiety constituent; 
 b. exposing said sol-gel film through a gray scale mask having a different region of opacity corresponding to each of said channels to light, wherein different amounts of light energy pass through each region of opacity in said gray scale mask, and wherein the light is of a wavelength and is delivered for a time sufficient to photolyze different concentrations of photosensitizer within a plurality of exposed regions of said sol-gel film corresponding to said channels and thereby unbind a different concentration of photolabile constituents from metal constituents within each of said channels; 
 c. heating said sol-gel film at a first temperature and for a time sufficient to drive off unphotolyzed photosensitizer and bind said different concentrations of said metal constituents to said sol-gel film in said channels permanently; and 
 d. heating said sol-gel film at a second relatively higher temperature for unbinding the organic constituents of said sol-gel film and for driving off the organic constituent.